1. Field of the Disclosed Embodiments
This disclosure relates to systems and methods for avoiding adhesion of particles to interior surfaces of fine orifices, particularly orifices in a stainless steel aperture or orifice plate for an inkjet printhead “jetstack,” during a high temperature adhesive bonding process used to fabricate the jetstack.
2. Related Art
Phase-change inkjet printing processes often employ inks that are presented as solids in the image forming device. Piezoelectric actuated printheads, referred to as “jetstacks” are used to delivery melted phase-change ink to the substrate where the ink cools to form a raised image.
FIG. 1 illustrates a typical configuration of a phase-change inkjet printhead jetstack 100. As shown in FIG. 1, the exemplary jetstack 100 often includes multiple laminated plates, sheets or layers stacked in a superimposed relationship. The multiple laminated plates, sheets or layers may be formed from different materials, which include stainless steel and polyimide, among others.
In the configuration of the exemplary jetstack 100 shown in FIG. 1, the following plates, sheets or layers may be included: a diaphragm plate 110, with multiple transducers 115, which may include one or more piezoelectric transducers on one surface; an ink pressure chamber plate 120; an inlet/outlet plate 130; an adhesive layer 140, an aperture brace plate 150 (also referred to as “support brace”), and an aperture plate 160, which may also be referred to as an orifice plate or jetstack front face plate. The aperture plate 160 will generally be made of stainless steel and be relatively thin. Typically, the aperture plate 160 and the aperture brace plate 150 are brazed together using, for example, a high temperature interface alloying process, to form an aperture plate/brace plate unit 160,150. The aperture plate/brace plate unit 160,150 may then be glued with the rest of the jetstack using the adhesive layer 140.
The exemplary jetstack 100 may include one or more ink pressure chambers 125 coupled to, or in fluid communication with, one or more ink inlets 170, via which ink is introduced into the exemplary jetstack 100 from one or more ink sources (not shown), and one or more ink ejection outlets, for example, apertures, orifices or nozzles (“apertures/orifices”) 165, via which ink is ejected as a stream of ink droplets 190. A typical inkjet printer includes a plurality of jetstacks with a plurality of ink pressure chambers 125 with each of the plurality of ink pressure chambers 125 being in fluid communication with one or more of the apertures/orifices 165. For simplicity and ease of understanding of the configuration of the exemplary jetstack 100 shown in FIG. 1, only two exemplary apertures/orifices 165 are depicted. Each aperture/orifice 165 may be in fluid communication with a respective ink pressure chamber 125 by way of the ink passages indicated by arrows 180. Ink can pass through apertures/orifices 165 during ink drop formation Ink drops can travel in a direction along the path of the stream 190 upon exiting the apertures/orifices 165 toward an image receiving medium (not shown) that is spaced from the aperture plate 160 and the apertures/orifices 165 in the aperture plate 160. The apertures/orifices 165 are thus formed in the aperture plate 160 on an outlet side of the exemplary jetstack 100.
In general then, the jetstack 100 comprises a stack of joined plates that have manifolds to route the ink from ink sources to the image receiving medium via an array of individual jets each ending in a respective aperture/orifice 165 from which ink is dispensed. The plates of the jetstack 100 are aligned such that respective holes in each plate form the ink passages indicated by the arrows 180. The respective holes in each of the layers other than the aperture plate layer may be of a same size or of varying sizes. Common to these devices is that the apertures/orifices 165 are of a significantly smaller cross-sectional dimension than the respective holes in each of the layers above the aperture plate 160.
In operation, the transducers 115 receive an activating signal, and upon activation, depress the portion of the diaphragm plate 110 with which they are associated exerting a pressurizing force on individual ones of the ink pressure chambers 125 pushing the ink downward along the vertical portion of the ink flow path 180 and ejecting the ink as droplets from the respective apertures/orifices 165.